1. Field of the Invention
This invention relates to an apparatus for detecting variation of at least one condition amount in various mechanical machines by utilizing variation of the impedance of at least one winding of an A.C. transformer (hereinafter, it is called a detecting transformer) due to open and close of the other winding thereof.
2. Description of Prior Art
In general, in a mechanical machine, it is accompanied with variation of the mechanical condition. For example, in a brake mechanism using a friction machine, the friction machine wears away in accordance with the used number of times or durability. Therefore, since the braking operation can not be effected if the friction machine wears away to unusable condition, the wear limit is predetermined and it is required to inform to the outside that the mechanical condition of said machine reached said limit when such situation occurs.
Generally, in a mechanical machine, there are variations of various mechanical conditions other than that in said brake mechanism. There are mechanical mechanism and an electrical detecting mechanism as such detecting mechanism for detecting variation of mechanical condition and at present the electrical detecting mechanism is frequently used. The electrical detecting mechanism is composed of a detecting element such as a transistor. This example using the transistor has reliability for a static type mechanical machine and a mechanical machine used under environment with a little temperature variation but little reliability for a vibrating type mechanical machine and a mechanical machine used under environment with large temperature variation.